Mass spectrometers are widely used for the detection of chemical substances. In a typical mass spectrometer, molecules or particles are excited or ionized, and these excited species often break down to form ions of smaller mass or react with other species to form other characteristic ions. The ion formation pattern can be interpreted by a system operator to infer the identity of the compound.
Biological molecules can sometimes be challenging to analyze using mass spectroscopic methods. In particular, transport and ionization of certain large biological molecules, prior to mass spectroscopic analysis, can represent a significant obstacle. Fluidic transport techniques can be used to handle such samples, while specialized ionization methods such as electrospray ionization have been developed to generate ions that can be subsequently analyzed.